Poster Presentation Society for Molecular Biology and Evolution Conference 2016

Parallel evolution of the auxin pathway in an Australian wildflower (#483)

Melanie J Wilkinson 1 , Federico Roda 1 2 , Maddie E James 1 , Henry L North 1 , Greg M Walter 1 , Christine A Beveridge 1 , Daniel Ortiz-Barrientos 1
  1. School of Biological Sciences, The University of Queensland, Brisbane, Queensland, Australia
  2. Department of Organismic and Evolutionary Biology, The Arnold Arboretum of Harvard University, Boston, MA, USA

Traits may repeatedly evolve in independent populations inhabiting similar environments. Whether this occurs with populations utilising different genetic mechanisms or the same genetic mechanisms (either through the same mutations, genes or biochemical pathway) remains largely unknown, leaving us ignorant to how evolution by natural selection proceeds at the molecular level. Here, we contribute to filling this gap with the Senecio lautus system, where populations have repeatedly evolved divergent growth forms in two contrasting adjacent environments. We use a combination of genetic, phenotypic and physiological experiments in natural and mapping populations to isolate the genetic mechanisms involved in the evolution of these two growth forms. Our results indicate that the auxin pathway, a pathway that controls plant growth and development is repeatedly differentiated in many natural populations adapting to contrasting environments. Furthermore, we found an auxin controlled phenotype, response to a change in gravity, to be divergent in many but not all independent S. lautus populations. Overall the results indicate that S. lautus populations use both the same and different genetic mechanisms in the evolution of growth form.